Ask A Scientist: Are The Northern Lights Radioactive?

If you didn’t grow up with the Northern Lights shining above you, the first few times you see them take your breath away. Even if you know they’re just charged solar particles, the colours and the movements are eerie. Have you ever wondered if any of that intense energy burning up in the sky was bad for you? No? Well, we did. So we asked Kjartan Guðnason and Benóný Þór Björnsson, specialists at the Icelandic Radiation Safety Authority, a question they’ve probably never been asked before:

Does radiation issue from the Northern Lights, even at trace levels, enough to reach the surface of the Earth? If so, what kind of radiation is it?

“Northern Lights appear when high energy particles from the sun collide with atoms and molecules in the atmosphere, causing them to emit light. This light (like all other light) is a form of electromagnetic radiation, which reaches the Earth along with radio waves, which are a different kind of electromagnetic radiation. X-ray radiation has also been detected from these collisions, but they are absorbed by lower parts of the Earth‘s atmosphere and do not reach the surface.

“So yes, when we see Northern Lights it is because radiation is being emitted, otherwise we would not be able to see them (light is radiation). And no, the Northern Lights themselves are no source of radiation but a manifestation of what is happening all the time (the sun emits energy). So the Northern Lights you see emit no radiation, but are themselves electromagnetic radiation emitted by collision between highly energetic solar particles and our atmosphere.”

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